The core of the build is a 16 bit microcontroller a dsPIC33FJ128GP802 from Microchip. It’s a humble chip to be doing so much. It uses a UBlox NEO-6M positioning module for the location and a custom built QFH antenna built after calculations done with an online calculator for the GPS half. The audio half is based around a VLSI VS1003b decoder chip.
The whole build is done with protoboard. Where the built in traces didn’t suffice enamel and wire wrap wire were carefully routed and soldered in place. There’s a 48pin LQFP package chip soldered dead bug style that’s impressive to behold. You can see some good pictures in this small gallery below.
If it wasn’t for the weird Dutch-Norwegian techno you’d presumably have to listen to forever, [Gianni B.]’s doll house for his daughter, [Rita] makes living in a Barbie World seem like a worthwhile endeavor. True to modern form, it’s got LED lighting. It’s got IoT. It’s got an app and an elevator. It even has a tiny, working, miniature television.
It all started with a Christmas wish. [Rita] could no longer stand to bear the thought of her Barbie dolls living a homeless lifestyle on her floor, begging passing toys for enough monopoly money to buy a sock to sleep under. However, when [Gianni] visited the usual suspects to purchase a dollhouse he found them disappointing and expensive.
So, going with the traditional collaborating-with-Santa ruse, he and his family had the pleasure of collaborating on a dollhouse development project. Each room is lit by four ultra bright LEDs. There is an elevator that’s controlled by an H-bridge module, modified to have electronic braking. [Rita] doesn’t own a Dr. Barbie yet, so safety is paramount.
The brain of the home automation is a PIC micro with a Bluetooth module. He wrote some code for it, available here. He also went an extra step and used MIT’s scratch to make an app interface for the dollhouse. You can see it work in the video after the break. The last little hack was the TV. An old arduino, an SD Card shield, and a tiny 2.4 inch TFT combine to make what’s essentially a tiny digital picture frame.
His daughter’s are overjoyed with the elevation of their doll’s economic class and a proud father even got to show it off at a Maker Faire. Very nice!
[Bruce Land] switched his microprocessor programming class over from Atmel parts to Microchip’s PIC32 series, and that means that he’s got a slightly different set of peripherals to play with. One thing that both chips lack, however is a digital-to-analog converter (DAC). Or do they? (Dun-dun-dun-duuuuhnnnn!)
The PIC part has a programmable, sixteen-level voltage reference. And what is a Vref if not a calibrated DAC? With that in mind, [Bruce] took to documenting its performance and starting to push it far beyond the manufacturer’s intentions. Turns out that the Vref has around 200 kHz of bandwidth. (Who would update a voltage reference 200,000 times per second?)
Anyway, [Bruce] being [Bruce], he noticed that the bits weren’t changing very often in anything more than the least significant bit: audio waveforms, sampled fast enough, are fairly continuous. This suggests using a differential PCM encoding, which knocks the bitrate down by 50% and saves a lot on storage. (Links to all the code for this experiment is inline with his writeup.)
It’s not just an LED-blinker, though. He added in a light-detection function so that it only switches on at night. It uses the Forest Mims trick of reverse-biasing the LED and waiting for it to discharge its internal capacitance. The point is, however, that it gives the chip something to do instead of simply sleeping.
Although he’s an AVR user by habit, [Thierry] finds in favor of the PIC because it’s got a lower power draw both when idling and when awake and doing some computation. This is largely because the PIC has an onboard low-power oscillator that lets it limp along at 32 kHz, but also because the chip has a lower power consumption in general. In the end, it’s probably a 10% advantage to the PIC on power.
If you’re competent with one of the two chips, but not the other, his two versions of the same code would be a great way to start familiarizing yourself with the other. We really like his isDarkerThan() function which makes extensive use of sleep modes on both chips during the LED’s discharge period. And honestly, at this level the code for the two is more similar than different.
(Oh, and did you notice [Thierry]’s use of a paper clip as a coin-cell holder? It’s a hack!)
Surprisingly, we’ve managed to avoid taking a stray bullet from the crossfire that occasionally breaks out between the PIC and AVR fans. We have covered a “shootout” before, and PIC won that round too, although it was similarly close. Will the Microchip purchase of Atmel calm the flames? Let’s find out in the comment section. We have our popcorn ready!
A camera slider is an accessory that can really make a shot. But when your business is photography rather than building camera accessories, quick-and-dirty solutions often have to suffice. Thus the genesis of this camera slider controller.
The photographer in question in [Paulo Renato], and while his passion may be photography, he seems to have a flair for motorized dollies and sliders. This controller is a variable-speed, reversible, PIC-based design that drives an eBay gearmotor. The circuit lives on a scrap of perfboard, and it along with batteries and a buck converter are stuffed into the case-modded remains of an old KVM switch. Push buttons salvaged from another bit of e-waste act as limit switches, and a little code provides the magic. We like the hacked nature of the controller, but we wonder about the wisdom of using the former KVM’s USB ports to connect the controller to the drivetrain; it’s all fun and games until you plug a real USB device into it. In sum, though, a nice build with nice results. Check out his other videos for more on the mechanicals.
On the surface, a cup of tea is a simple thing to make. Heat up some water, insert tea leaves, and wait for it to steep. The wait time is a matter of taste, and it is absolutely crucial to remove the bag or infuser before it’s too late. Otherwise, you end up with a liquid that’s almost, but not quite, entirely unlike tea.
[Adrian] and his son would often find themselves lost in conversation during the steeping process and let it go too long. But that was before they built ChaiBot, an automatic tea minder. This fine-looking machine uses an old CD drive to raise and lower the tea bags, which are held by a thin piece of stainless steel mesh. Once the bags are lowered, [Adrian] pours hot water into the cups. The weight of the water is detected by a capacitive sensor under the cup cutouts, and this triggers the timer to start counting down to the perfect cuppa.
One of the coolest features of ChaiBot is the built-in circulation. Every minute, the bags are lifted out briefly and reinserted, disturbing the water so the steeping is more uniform. Since the final step to making great tea is drinking it before it goes cold, ChaiBot sends a push notification to [Adrian]’s phone. Be sure to check out the demo after the break.
We are just two weeks away from the Hackaday | Belgrade conference, and tickets have completely sold out. That means you can’t get your hands on one of these sweet hardware badges, but you can still take home some prizes for pulling off a gnarly hack with the badge firmware.
What we’re talking about is the Hackaday Belgrade Badge Demoscene – which includes a surrogate presenter program for anyone who wants to send in their own code for the device. You have two weeks to work on and submit your code — and we’ve made it really easy for anyone who has a working knowledge of C.
The day of the conference we will download all entries, and have a surrogate at the conference load it onto their badge and present it on your behalf. There is a separate pool of prizes for online entries, so hackers not at the con will win. And of course we’ll be celebrating the awesome demos with some posts on the front page.
No Hardware Needed
Hack in C for Abstracted Bliss or Be Hardcore:
You can use the emulator shown here to write your code for this badge. It comes with a set of basic functions that abstracts away the low-level hardware functions, and launches a demo window on your computer to test out your code. Check out this barebones C framework to get started.
For those that want more control, we have published the official assembly code that the badges will ship with (including a user manual). We’ll be squashing bugs right up to the day of the con). You can alter and compile this code yourself, or just start from scratch using the design spec if you prefer to travel the hardcore bit-monkey path.
Either way, you have an 8×16 display and 4 buttons to work with. Exercise your creativity and amaze us by doing a lot on a rather modest canvas. That’s what demoscene is all about.
How to Enter
Entry is easy, just start a project on Hackaday.io and submit it to the Belgrade Badge Demoscene contest using the “Submit Project To…” menu on your project page. You need to upload .C and .H files, or a precompiled .HEX to the file hosting part of your project page by Saturday, April 9th.
That’s the extent of the requirements. But it would be super fun if you recorded the software emulator playing your demo for all to see. The easiest way to do this is to record a video of your computer screen using your smartphone. Good luck to all!